Aircraft retrieval system and method

ABSTRACT

The present disclosure describes various systems, devices, and methods configured to retrieve a fixed-wing aircraft from free flight using a flexible capture member

PRIORITY CLAIM

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 62/851,360, which was filed on May 22, 2019, theentire contents of which is incorporated herein by reference.

BACKGROUND

Aircraft capable of long-distance, efficient cruising flight typicallyrequire long runways for take-off and landing. This limits the locationsfrom which the aircraft can take-off and at which the aircraft can land,since many locations don't have sufficient space for a runway. There isa continuing need for new systems and methods that eliminate the needfor these aircraft to use long runways to take-off and land.

In one known system, a rope is extended in an upright orientationbetween a first device at a high point and a second device at a lowpoint. A fixed-wing aircraft is then flown such that it contacts therope with its wing between the high point and the low point, therebyenabling the aircraft to capture the rope. The contact between thefixed-wing aircraft and the rope can involve relatively high forces thatmust be absorbed by the system to stop the fixed-wing aircraft.Depending on where along the rope the fixed-wing aircraft makes contact,the force may be absorbed more by either the first device or the seconddevice. When the fixed-wing aircraft makes contact toward the highpoint, the first device must absorb a large percentage of the impartedforce from the contact. When the first device is a multi-copter, suchforce requires the multi-copter to expend more energy to remain inflight and support the rope and captured fixed-wing aircraft.Alternatively, when the fixed-wing aircraft makes contact toward the lowpoint, more of the impact force is applied to the second device. Whenthe second device is a tall structure, with a height exceeding that ofthe fixed-wing aircraft wingspan for which it is configured to retrieve,for example, to keep the fixed-wing aircraft a safe distance above thesurface, post-retrieval, the risk of tipping over increases. Thus, thereis a need for improved aircraft retrieval devices that address theseissues.

BRIEF SUMMARY

Various embodiments of the present disclosure provide systems andmethods for retrieving a fixed-wing aircraft from free flight thataddress the above described issues.

One example system of the present disclosure includes: (1) a liftingdevice used to raise a first end of a flexible capture member to apredetermined height; and (2) an aircraft retrieval device including atensioning device (such as a downhaul winch) coupled to the second endof the flexible capture member and a monopole assembly positioned abovethe tensioning device. The flexible capture member extends through themonopole assembly. In various embodiments, the aircraft retrieval devicefurther includes a storage assembly usable to store the monopoleassembly, tensioning device, and flexible capture member whendisassembled, and to provide a platform on which the monopole assemblyand tensioning device are supported during capture of the fixed-wingaircraft. In certain example embodiments, the base of the monopoleassembly may be articulatable, and in other example embodiments, themonopole itself may be articulatable, while in still other exampleembodiments both the monopole and the base of the monopole assembly arearticulatable. This may further minimize the footprint and mass of theequipment.

One example method of the present disclosure employs a downhaul winch,the monopole assembly, the flexible capture member, and the liftingdevice to capture the fixed-wing aircraft and lower it toward theground. More specifically, to retrieve the fixed-wing aircraft fromfree, wing-borne flight, the method includes: (1) attaching a free endof the flexible capture member to the lifting device (e.g., arotorcraft, crane, boom, parachute, etc.)) such that the flexiblecapture member extends from a drum of the downhaul winch through themonopole assembly to the lifting device; (2) controlling the liftingdevice to raise the first end of the flexible capture member to adesignated altitude above the monopole assembly, the downhaul winch, andthe storage assembly; (3) controlling the fixed-wing aircraft to contactand capture the flexible capture member, preferably at a positionrelatively close to the monopole assembly; and (4) controlling thelifting device to descend such that the fixed-wing aircraft is loweredand supported by the monopole assembly in its most-upright position.

Additional features and advantages of the present disclosure aredescribed in, and will be apparent from, the following DetailedDescription and the Figures.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a top perspective view of an example multi-copter of oneexample embodiment of the present disclosure and an example fixed-wingaircraft of one example embodiment of present disclosure and shownattached to the multi-copter.

FIG. 1B is a top plan view of the multi-copter and the fixed-wingaircraft of FIG. 1A.

FIG. 1C is a top perspective view of the multi-copter of FIG. 1A.

FIG. 1D is a bottom perspective view of the multi-copter of FIG. 1A.

FIG. 2A is a top perspective view of a first example storage assembly(including a gas generator) of one example embodiment of the presentdisclosure.

FIG. 2B is top perspective view of a second example storage assembly(including a diesel generator) of another example embodiment of thepresent disclosure.

FIGS. 3A and 3B are top perspective views of an example downhaul winchof one example embodiment of the present disclosure.

FIG. 3C is a partially exploded top perspective view of the downhaulwinch of FIGS. 3A and 3B.

FIGS. 3D and 3E are partially exploded top perspective views of thedownhaul winch of FIGS. 3A and 3B shown with certain components removed.

FIG. 4A is a front perspective view of an example aircraft retrievaldevice of one example embodiment of the present disclosure, and shownsupported by the one of the storage assemblies of the presentdisclosure.

FIG. 4B is a front perspective view of the aircraft retrieval device ofFIG. 4, shown after an aircraft has been retrieved by the aircraftretrieval device, and shown supported by one of the storage assembliesof the present disclosure.

FIG. 4C is an enlarged perspective view of an example articulating jointof an articulatable monopole assembly of the aircraft retrieval deviceof FIG. 4A, and shown supported by one of the storage assemblies of thepresent disclosure shown in fragmentary.

FIG. 4D is an exploded view of the articulating joint of thearticulatable monopole assembly of FIG. 4C, and showing one of thestorage assemblies of the present disclosure.

FIG. 4E is a side perspective view of the aircraft retrieval device ofFIG. 4A experiencing a sideways force from the flexible capture member,and shown supported by one of the storage assemblies of the presentdisclosure.

FIG. 4F is a cross-sectional view of an upper portion of thearticulatable monopole assembly of the aircraft retrieval device of FIG.4A taken substantially along a midline of the articulatable monopoleassembly.

FIG. 4G is a top perspective view of an upper guiding sealing componentof the articulatable monopole assembly of FIG. 4F.

FIG. 4H is a cross-sectional view of the upper guiding sealing componentof FIG. 4G taken substantially along line 4H-4H of FIG. 4G.

FIG. 5A is a diagrammatic view of the multi-copter and fixed-wingaircraft of FIG. 1A, and the aircraft retrieval device of FIG. 4A, shownjust before the fixed-wing aircraft captures the flexible capturemember.

FIG. 5B is a diagrammatic view of the multi-copter and fixed-wingaircraft of FIG. 1A, and the aircraft retrieval device of FIG. 4A, shownjust after the fixed-wing aircraft captures the flexible capture member,illustrating how the articulatable monopole assembly articulates toreduce the overturning moment of the base, and showing that thearticulatable monopole assembly has absorbed at least part of the impactforce from the fixed-wing aircraft without toppling, and shown supportedby one of the storage assemblies of the present disclosure.

FIG. 5C is a diagrammatic view of the multi-copter and fixed-wingaircraft of FIG. 1A, and the aircraft retrieval device of FIG. 4A, shownafter the fixed-wing aircraft has stopped moving sideways and thedownhaul winch has retracted a portion of the flexible capture member,and shown supported by one of the storage assemblies of the presentdisclosure.

FIG. 5D is a diagrammatic view of the multi-copter and fixed-wingaircraft of FIG. 1A, and the aircraft retrieval device of FIG. 4A, shownafter the fixed-wing aircraft has been lowered safely to the monopoleassembly and the multi-copter has landed, and shown supported by one ofthe storage assemblies of the present disclosure.

FIG. 6A is a perspective view of an example aircraft retrieval device ofanother example embodiment of the present disclosure and shown supportedby one of the storage assemblies of the present disclosures.

FIG. 6B is another perspective view of the example aircraft retrievaldevice of FIG. 6A, with the monopole assembly removed and shownsupported by one of the storage assemblies of the present disclosure.

FIG. 6C is an enlarged perspective view of a base of the monopoleassembly of the aircraft retrieval device of FIG. 6A and shown supportedby one of the storage assemblies of the present disclosure.

FIG. 6D is an enlarged side perspective view of the connection betweentwo sections of an outrigger of the aircraft retrieval device of FIG.6A.

FIG. 6E is a perspective view of the example aircraft retrieval deviceof FIG. 6A shown in and supported by one of the storage assemblies ofthe present disclosure.

FIG. 7A is a fragmentary perspective view of a top portion of an examplemonopole assembly that has captured mocked-up fixed-wing aircraft, themonopole assembly including a castellated masthead according to anotherexample embodiment of the present disclosure.

FIG. 7B is a fragmentary perspective view of the monopole assemblyincluding the castellated masthead of FIG. 7A, and showing part of thecaptured mocked-up fixed-wing aircraft.

FIG. 7C is an enlarged fragmentary perspective view of the castellatedmasthead attached to the top of the monopole assembly of FIG. 7A.

FIG. 7D is a perspective view of the castellated masthead of FIG. 7A.

DETAILED DESCRIPTION

While the features, methods, devices, and systems described herein maybe embodied in various forms, there are shown in the drawings, and willhereinafter be described, some exemplary and non-limiting embodiments.Not all of the depicted components described in this disclosure may berequired, however, and some implementations may include additional,different, or fewer components from those expressly described in thisdisclosure. Variations in the arrangement and type of the components;the shapes, sizes, and materials of the components; and the manners ofattachment and connections of the components may be made withoutdeparting from the spirit or scope of the claims as set forth herein.This specification is intended to be taken as a whole and interpreted inaccordance with the principles of the disclosure as taught herein andunderstood by one of ordinary skill in the art. The drawings are not toscale unless noted otherwise.

The present disclosure describes various systems, devices, and methodsfor retrieving a fixed-wing aircraft from free flight. At a relativelyabstract level, the aircraft retrieval system of the present disclosureoperates by raising a first end of a flexible capture member to apredetermined height (such as by, but not limited to, using amulti-copter), and coupling a second end of the flexible capture memberto a second device on the ground (such as but not limited to a winch).The fixed-wing aircraft is then controlled to contact the flexiblecapture member between the first and the second ends of the flexiblemember, whereby the fixed-wing aircraft captures the flexible capturemember and is thereafter lowered toward the ground.

In many situations, it is beneficial for the fixed-wing aircraft tocontact the flexible capture member as close to the ground or second endof the flexible capture member as possible. The fixed-wing aircraft mayoperate using guidance information based on a GPS receiver positioned ina base of the aircraft retrieval device, which is positioned near thesecond end of the flexible capture member. The first end (or high end)of the flexible capture member may sway or move in the air due to windand movement of the multi-copter. This movement is reduced near thesecond end (or low end) of the flexible capture member. When thefixed-wing aircraft attempts to make contact near the low end, it has anincreased likelihood of actually making contact with the flexiblecapture member at an expected location relative to the aircraftretrieval device, and at an expected span-wise position on the aircraftwing. Additionally, it is beneficial for the fixed-wing aircraft tocontact the flexible capture member close to the low end to reduce theflight time required of the multi-copter. After the fixed-wing aircraftcaptures the flexible capture member, the aircraft and flexible capturemember are fully supported by the multi-copter. This requires themulti-copter to use additional energy to remain in flight. When thefixed-wing aircraft captures the flexible capture member close to thelow end, the amount of time required to lower the aircraft is less thanwhen the fixed-wing aircraft captures the flexible capture member closeto the high end. A further benefit relates to the relative ability ofthe multi-copter and the downhaul winch to absorb the energy from theimpact of the fixed-wing aircraft on the flexible capture member. Themulti-copter is less able to absorb impact energy than the downhaulwinch. As such, it is beneficial for the fixed-wing aircraft to contactthe flexible capture member closer to the low end where the downhaulwinch is position, such that a greater portion of the impact energy istransferred to the downhaul winch.

One drawback of controlling the fixed-wing aircraft to contact theflexible capture member at a relatively low height is that thefixed-wing aircraft imparts a high overturning moment on the structureon the ground. If the ground structure is too rigid and/orinsufficiently ballasted, it can tip over when the impact energy istransferred through the flexible capture member.

As described in further detail below and with respect to the Figures,the issues discussed above are addressed by the example aircraftretrieval system disclosed herein. To mitigate the issue of tippingover, and to take advantage of the benefits of a low contact point onthe flexible capture member, various example embodiments of the aircraftretrieval system of the present disclosure include: (1) a lifting deviceconfigured to raise the first end of the flexible capture member to apredetermined height above an example aircraft retrieval device, and (2)an aircraft retrieval device including a monopole assembly such as anarticulatable monopole assembly.

The lifting device may be any suitable device configured to raise thefirst end of the flexible capture member. For example, the liftingdevice may be a multi-copter, crane, boom, aircraft, parachute, or otherdevice. In the embodiment shown in the Figures, the lifting device is amulti-copter 10. As such, the multi-copter 10 is described in furtherdetail below. However, it should be appreciated that the lifting devicemay be any other suitable device for raising the first end of theflexible capture member.

The illustrated example aircraft retrieval device includes a storageassembly 2000, a downhaul winch 3000, an articulatable monopole assembly4000, and a flexible capture member 5000. These example elements aredisclosed in further detail below with respect to the Figures.

1. Multi-Copter

FIGS. 1A, 1B, 1C, and 1D show one example multi-copter indicated bynumeral 10. The multi-copter 10 is modular in that it is assembled from(and can be disassembled into) a plurality of different modules orsubassemblies. The multi-copter 10 is removably attachable to: (1) thefixed-wing aircraft 20 (to facilitate launch of the fixed-wing aircraft20 into free, wing-borne flight), and (2) the downhaul winch 3000 viathe flexible capture member 5000 (for retrieval of the multi-copter 10following launch of the fixed-wing aircraft 20, and retrieval of boththe fixed-wing aircraft and multi-copter 10 after the fixed-wingaircraft 20 has captured the flexible capture member 5000).

While the multi-copter 10 includes eight rotors in the exampleembodiments described below and shown in FIGS. 1A-D, the aircraftretrieval system may include any suitable rotorcraft including anysuitable quantity of rotors, such as one rotor, two rotors, or fourrotors.

The multi-copter 10 includes several modules or subassemblies,including: a hub module; first, second, third, and fourth rotor armmodules; first and second front landing gear extension modules; firstand second rear landing gear extension modules; first and second frontlanding gear modules; and first and second rear landing gear modules.

As described in detail below, to assemble the multi-copter 10 from thesemodules or subassemblies, after removing the modules from the containerof the storage assembly 2000, an operator: (1) attaches the first,second, third, and fourth rotor arm modules to the hub module; (2)attaches the first and second front landing gear extension modules tothe first and second rotor arm modules, respectively; (3) attaches thefirst and second rear landing gear extension modules to the third andfourth rotor arm modules, respectively; (4) attaches the first andsecond front landing gear module to the first and second front landinggear extension modules, respectively; and (5) attaches the first andsecond rear landing gear module to the first and second rear landinggear extension modules, respectively.

The modularity of this multi-copter is beneficial compared tonon-modular or unitary multi-copter construction. First, the modularityof this multi-copter enables an operator to quickly and easilydisassemble this relatively large multi-copter into smaller modules orsubassemblies. The operator can compactly store these modules orsubassemblies into a single container, which makes the disassembledmulti-copter easy to store and transport compared to the assembledmulti-copter. Second, if a part of this multi-copter breaks, itsmodularity enables the operator to quickly and easily replace themodule(s) or subassembly(ies) including the broken part with a properlyfunctioning replacement module(s) or subassembly(ies) rather than wastetime repairing the broken component(s).

The multi-copter 10 may include various electronic components, such asbut not limited to: (1) a controller; (2) a communications interface;(3) an inertial measurement unit (IMU); (4) a barometer (or othersuitable pressure sensor); (5) a GPS receiver; and (6) eight electronicspeed controllers (ESCs). The multi-copter 10 may also include variousmotors, such as a cam servo motor, a lock servo motor, and a pluralityof rotor motors to control each of the rotors.

The controller is electrically and communicatively connected to thecommunications interface, the IMU, the barometer, the GPS receiver, theESCs, the cam servo motor, and the lock servo motor. The controllerincludes a processor and a memory. The processor is configured toexecute program code or instructions stored in the memory to controloperation of the multi-copter 10, as described herein. The processor maybe one or more of: (1) a general-purpose processor; (2) acontent-addressable memory; (3) a digital-signal processor; (4) anapplication-specific integrated circuit; (5) a field-programmable gatearray; (6) any suitable programmable logic device, discrete gate, ortransistor logic; (7) discrete hardware components; and (8) any othersuitable processing device.

The memory is configured to store, maintain, and provide data as neededto support the functionality of the multi-copter 10. For instance, invarious embodiments, the memory stores program code or instructionsexecutable by the processor to control the multi-copter 10. The memorymay be any suitable data storage device, such as one or more of: (1)volatile memory (e.g., RAM, which can include non-volatile RAM, magneticRAM, ferroelectric RAM, and any other suitable forms); (2) non-volatilememory (e.g., disk memory, FLASH memory, EPROMs, EEPROMs,memristor-based non-volatile solid-state memory, etc.); (3) unalterablememory (e.g., EPROMs); and (4) read-only memory.

The communications interface is a suitable wireless communicationinterface, such as a transceiver like an MM2 900 MHz Embedded Radio byFreewave Technologies, configured to establish and facilitatecommunication between the controller and: (1) a computing device (suchas a laptop computer, a tablet computer, or a mobile phone, not shown);and (2) an R/C controller (not shown) that the operator of themulti-copter 10 controls. In operation, once the communicationsinterface establishes communication with the computing device, thecontroller can send data (via the communications interface) associatedwith the operation of the multi-copter 10 (such as the operationalstatus of the multi-copter 10, GPS coordinates of the multi-copter 10,rotor motor status, IMU or other sensor measurements, altitude, GPSreception health, magnetometer health, attitude, and the like) to thecomputing device. Once the communications interface establishescommunication with the R/C controller, the controller can receivesignals (via the communications interface) from the R/C controller. Morespecifically, upon receipt of these signals from the R/C controller, thecommunications interface converts these signals into a format readableby the controller and sends the converted signals to the controller forprocessing.

The IMU may include one or more accelerometers, gyroscopes, and/ormagnetometers. The accelerometers, gyroscopes, and magnetometerscontinuously or periodically obtain sensor readings and continuously orperiodically transmit corresponding signals to the controller, whichuses these sensor readings in a variety of different ways describedherein. This is merely one example IMU, and the IMU may include anysuitable sensors.

The barometer is configured to sense the atmospheric pressure and totransmit a signal representing the sensed atmospheric pressure to thecontroller. This information may be used to determine a height of themulti-copter 10.

The GPS receiver is communicatively connectable with (such as via asuitable wireless protocol) GPS satellites (not shown), as is known inthe art. The GPS receiver is configured to receive signals from one ormore of the GPS satellites, to determine the multi-copter's locationusing those signals, and to transmit signals representing themulti-copter's location to the controller.

The ESCs are electrically connected to and, along with the controller,control the operation of the rotor motors of the multi-copter 10.

The multi-copter 10 includes a hub module, to which the fixed-wingaircraft 20 is attached for launch, and to which a flexible capturemember 5000 is attached to retrieve the fixed-wing aircraft from flight.The hub module includes a hub base and a saddle. The saddle is attachedto the underside of the hub base. The hub module also includes aflexible capture member storage device (not shown) attached to the hubbase and/or the saddle. The flexible capture member storage device isconfigured to store and release the flexible capture member to enableretrieval of the multi-copter 10 via the downhaul winch 3000.

2. Storage Assembly

FIG. 2A shows a first example storage assembly. FIG. 2B shows a secondexample storage assembly. The first example storage assembly includes agas generator 2010. The second example storage assembly includes adiesel generator 2020. Additional items may be stored in the samecontainer as the articulatable monopole assembly, such as a batterycharger for the multi-copter, the retrieval rope (which functions as aflexible capture member) and bungee, and an engine cooling module forcontrolling fixed-wing aircraft engine temperature during preflight. Thefirst example storage assembly and the second example storage assemblyinclude many similar or identical features that are described togetherherein with respect to a single example storage assembly 2000. Thestorage assembly 2000 is usable to compactly store the downhaul winch3000, the articulatable monopole assembly 4000, the flexible capturemember 5000, and a generator 2010 or 2020 in a single container. Thestorage assembly 2000 also facilitates retrieval of the fixed-wingaircraft 20 from free, wing-borne flight by acting as a base on whichthe downhaul winch 3000 and the articulatable monopole assembly 4000 canbe mounted and supported during the retrieval process.

The multi-copter 10 may be stored (disassembled) in a separate storageassembly (not shown).

To facilitate storage of the generator 2010 or 2020, the downhaul winch3000, and the articulatable monopole assembly 4000 in a singlecontainer, the storage assembly 2000 includes: (1) a container top 2100and container bottom 2200, (2) a monopole mounting assembly 2300, and(3) space for the various components including the generator 2010 or2020, the downhaul winch 3000, the components of articulatable monopoleassembly 4000, etc.

The container top 2100 and container bottom 2200 are sized to fit thevarious components. The container top 2100 and/or container bottom 2200may include one or more storage brackets (not labeled) that are used toaffix the various components to the storage assembly 2000, in order toavoid shifting or movement of the components during transit. Thecontainer top 2100 and container bottom 2200 are configured to connectto each other via a plurality of latches 2110, and are completelyseparable from each other. The container top 2100 and container bottom2200 are formable into a “T” shape as shown in FIGS. 4A, 4B, 4C, and 4E,particularly during the process of retrieval of the fixed-wing aircraft20.

Alternatively, as further described below, the articulatable monopoleassembly may be mounted toward one end of the storage container, and oneor more such as a pair of outriggers may pivot outwardly to form a broadtriangular footprint. When two outriggers are employed, two points ofthe triangle are defined by the respective outrigger feet, and the thirdpoint is at the far end of the container. The lid may be used to securethe outriggers, keeping the triangular footprint as broad as possible.The outriggers may be telescopic subassemblies, to further-broaden thefootprint. By broadening the footprint, the support structure for thearticulatable monopole assembly may be kept light, which provides adistinct advantage when the equipment must be moved by humans.

The storage assembly 2000 also includes the monopole mounting assembly2300. The monopole mounting assembly includes: (1) a first containermounting bracket 2310, (2) a second container mounting bracket 2320, and(3) a lateral monopole support plate 2330.

The first container mounting bracket 2310 is affixed to an inner wall ofthe container bottom 2200 via two fasteners 2312 a and 2312 b. The firstcontainer mounting bracket 2310 is affixed to the container bottom 2200at a midpoint or central point of the container bottom 2200, asillustrated in FIGS. 2A and 2B. The fasteners may be screws, bolts, orany other type of fastener. The first container mounting bracket 2310 isalso affixed to the lateral monopole support plate 2330. The firstcontainer mounting bracket 2310 may be affixed to the lateral monopolesupport plate 2330 by welding, one or more fasteners, or by some othermechanism.

The second container mounting bracket 2320 is similar or identical tothe first container mounting bracket 2310, but with a flipped ormirrored orientation.

The lateral monopole support plate 2330 extends laterally across theopen side of the container bottom 2200. The top surface of the lateralmonopole support plate 2330 is even with the top edge of the containerbottom 2200. In some examples, the lateral monopole support plate 2330may be set into the container bottom 2200, such that a top surface ofthe lateral monopole support plate 2330 is below the top edge of thecontainer bottom 2200. The lateral monopole support plate extendslaterally across a middle of the container bottom 2200, as shown best inFIGS. 2A and 2B.

The lateral monopole support plate 2330 includes four monopole basemounting bolts 2310 a-d. The monopole base mounting bolts 2310 a-dextend upwardly from a top surface of the lateral monopole support plate2320. The monopole base mounting bolts 2310 a-d are configured to extendthrough corresponding apertures of the monopole base 4100 of thearticulatable monopole assembly 4000. The lateral monopole support plate2330 includes a top surface that defines a central aperture 2332. Thecentral aperture 2332 is circular, and is configured to receive thelower sealing and mounting component 3900 of the downhaul winch 3000.The flexible capture member 5000 of the downhaul winch 3000 isconfigured to extend from the downhaul winch 3000, through the centralaperture 2332, and through a channel defined by the articulatablemonopole assembly 4000. The central aperture 2332 is also positioned toalign with a central axis of the articulatable monopole assembly 4000.

The storage assembly 2000 also includes a container connection bracket2400. The container connection bracket 2400 is best illustrated in FIG.4C. The container connection bracket extends from the lateral monopolesupport bracket 2330 to a first end of the container top 2100. Thecontainer top 2100 includes top side connection members 2110 a and 2110b, configured to attach to the container connection bracket 2400. Thecontainer connection bracket 2400 enables the container top 2100 andcontainer bottom 2200 to be locked into a “T” shape for retrieval of thefixed-wing aircraft. This orientation provides increased stability whenthe articulatable monopole assembly 4000 is erected, and when forces areimparted onto the articulatable monopole assembly 4000 and storageassembly 2000 during capture of the fixed-wing aircraft. The likelihoodof the storage assembly 2000 and articulatable monopole assembly 4000tipping over during capture of the fixed-wing aircraft is reduced.

3. Downhaul Winch

The embodiment shown in the Figures includes a tensioning device in theform of the downhaul winch 3000. As such, an example downhaul winch 3000is described in further detail below. It should be appreciated, however,that the downhaul winch 3000 is only one example device that can be usedto provide tension to the flexible capture member used in retrieval ofthe fixed-wing aircraft. Other tensioning devices can include, forexample, a bungee, a piston, or a moving weight. Each of thesetensioning devices may be connected to the low end of the flexiblecapture member to provide a resistive force on the flexible capturemember, thereby maintaining tension. Although the tensioning device cantake various forms, the embodiment disclosed herein may be describedonly in the context of downhaul winch 3000.

The downhaul winch 3000 and components thereof is shown in FIGS. 3A-3E.The downhaul winch 3000 is usable along with the multi-copter 10, theflexible capture member 5000 (described below), and the articulatablemonopole assembly 4000 (described below) to retrieve the fixed-wingaircraft 20 from free, wing-borne flight. Generally, the components ofthe downhaul winch 3000 operate together to impose a regulated force onthe flexible capture member 5000 during the fixed-wing aircraftretrieval process. This means that the downhaul winch 3000 is configuredto regulate—i.e., maintain substantially constant—the tension in theflexible capture member 5000 while the multi-copter 10 isstation-keeping relative to the downhaul winch 3000 in preparation forretrieval of the fixed-wing aircraft 20. This simplifies multi-copteroperation during the fixed-wing aircraft retrieval process byeliminating the need for the multi-copter operator to control thealtitude of the multi-copter 10 to maintain a desired tension in theflexible capture member 5000.

The downhaul winch 3000 includes a winch base 3100, a first mountingbracket 3200, a second mounting bracket 3300, a separator bracket 3400,and a flexible capture member payout and retract system (not labeled).The flexible capture member payout and retract system includes a drumassembly 3500, a level wind system 3600, a transition assembly 3700, anda hydraulic system (not labeled).

3.1 Winch Base and Brackets

The winch base 3100 serves as a mount for certain other elements of thedownhaul winch 3000. As best shown in FIGS. 3A-3E, the winch base 3100includes two spaced-apart, generally parallel sides 3102 and 3104 and atop 3106 transverse (such as generally perpendicular) to, extendingbetween, and connecting the sides 3102 and 3104. As best shown in FIG.3C, the top 3106 includes a surface 3106a that defines a GPS antennamounting opening. The GPS antenna 3800 is attached to a mounting bracket(not labeled) that extends between the sides 3102 and 3104 such that theGPS antenna 3800 extends through the GPS antenna mounting opening of thetop 3106. As described below, a lower sealing and mounting component3900 is attachable to the top 3106 of the winch base 3100 via the lowersealing and mounting component mounting opening to attach thearticulatable monopole assembly 4000 to the down winch base 3100.

The first and second mounting brackets 3200 and 3300 serve as mounts forthe drum assembly 3500 and part of the hydraulic system (not labeled).As best shown in FIGS. 3D and 3E, the first and second mounting brackets3200 and 3300 are generally planar and include respective cylindricalsurfaces 3200 a and 3300 a that respectively define first and secondmounting openings through the first and second mounting brackets 3200and 3300. The first mounting bracket 3200 is attached to the first side3102 of the winch base 3100 via suitable fasteners (not shown), and thesecond mounting bracket 3300 is attached to the second side 3104 of thewinch base 3100 via suitable fasteners (not shown). The separatorbracket 3400 is attached to and extends between the first and secondmounting brackets 3200 and 3300 via suitable fasteners (not shown) tomaintain the spacing between these components.

3.2 Drum Assembly

The flexible capture member 5000 may be wound onto and off of the drumassembly 3500. The drum assembly 3500 may include various componentsconfigured to enable the drum assembly 3500 to wind and unwind theflexible capture member, and to maintain a set tension level on theflexible capture member 5000. For example, the drum assembly 3500 mayinclude a drum having a cylindrical exterior surface and a cylindricalinterior surface; a first drum flange having a circular exteriorsurface, a circular interior surface, a cylindrical perimeter surface,and a cylindrical mounting surface that defines a mounting openingthrough the first flange 3512; a second drum flange having a circularexterior surface, a circular interior surface, a cylindrical perimetersurface, and a cylindrical mounting surface that defines a mountingopening through the second flange; a drum shaft; a coupler including atubular coupler shaft defining a shaft-receiving bore therethrough and acoupler flange extending radially outwardly from the coupler shaft; afirst annular flange; a second annular flange; and a third annularflange.

3.3 Level Wind System

The level wind system 3600 ensures that the flexible capture member 5000is wound onto (and off of) the drum assembly 3500 in a generally uniformmanner. The level wind system 3600 includes a level wind shaft, a firsttraveler, a second traveler, a guide shaft, a first pulley, a secondpulley, and a belt (all not labeled).

In operation, as the drum shaft of the drum assembly 3500 rotates, thesecond pulley rotates therewith. Rotation of the second pulley causesthe first pulley to rotate due to their connection via the belt.Rotation of the first pulley causes the level wind shaft to rotate.Rotation of the level wind shaft causes the first and second travelersto slide relative to the level wind shaft due to their guide elementsbeing received in the grooves defined in the level wind shaft. Thissliding of the first and second travelers (which is keyed to rotation ofthe drum shaft) guides placement of the flexible capture member 5000 asit is wound onto (or off of) the drum.

3.4 Transition Assembly

The transition assembly 3700 is configured to route the flexible capturemember 5000 from the articulatable monopole assembly 4000 to the levelwind system 3600. As best shown in FIG. 3C, the transition assembly 3700includes a first transition assembly housing portion 3710, a secondtransition assembly housing portion 3720, a transition pulley 3730, anda fastener 3740. The first and second transition assembly housingportions 3710 and 3720 are attachable to one another via the fastener3740, and together define a transition pulley cavity and a flexiblecapture member receiving bore in fluid communication with the transitionpulley cavity. The transition pulley 3730 is rotatably mounted on aspindle (not labeled) within the transition pulley cavity such that thetransition pulley 3730 can rotate relative to the first and secondtransition assembly housing portions 3710 and 3720. The transitionassembly 3700 is attachable to the lower sealing and mounting component3900, which in turn is slidably receivable on the winch base 3100.

4. Monopole Assembly

As mentioned above, the force of contact by the fixed-wing aircraft 20on the flexible capture member 5000 can cause issues for themulti-copter 10 in maintaining flight. This can result in damage to themulti-copter 10 or fixed-wing aircraft 20. In certain situations, amonopole assembly such as an articulatable monopole assembly 4000 of thepresent disclosure is employed to partially absorb the force of impactwhen the fixed-wing aircraft 20 contacts the flexible capture member5000. The use of the monopole assembly such the articulatable monopoleassembly 4000 provides various benefits, such as those described above,as well as by enabling a smaller ground footprint to be used forcapturing the fixed-wing aircraft. As noted above, the monopole assemblysuch as the articulatable monopole assembly 4000 enables an aircraft tocontact the flexible capture member 5000 closer to the ground than wouldotherwise be possible, while minimizing the risk of the monopoleassembly such as the articulatable monopole assembly 4000 tipping over.It should be appreciated that when capturing a fixed-wing aircraft usinga flexible capture member, such as described herein with respect toFIGS. 5A-D, it may be beneficial for the fixed-wing aircraft to contactthe flexible capture member as low as possible toward the ground. Thisis for three reasons and particularly, navigation, energy absorption,and reduced flight time.

First, when the flexible capture member is extended into the air tocapture the fixed-wing aircraft, wind and other factors can cause theflexible capture member to sway or move. The flexible capture membermoves a smaller distance closer to the ground, meaning that thefixed-wing aircraft is more likely to make contact with the flexiblecapture member at the prescribed location and position on the aircraftwing if it makes contact close to the ground.

Second, when the fixed-wing aircraft contacts the flexible capturemember, the aircraft is travelling at a relatively high speed. Theenergy from the impact of the fixed-wing aircraft on the flexiblecapture member must be absorbed in order to bring the aircraft to astop. In the embodiment of FIGS. 5A-D, the flexible capture member isheld aloft by the multi-copter 10 above the contact point, and by thedownhaul winch 3000 below the contact point. The downhaul winch 3000 ismore able to absorb the impact energy without any ill effects than themulti-copter 10. As such, it is beneficial for the contact point to becloser to the downhaul winch 3000 than to the multi-copter 10.

Third, the multi-copter 10 is required to maintain a given altitudeduring the process of retrieving the fixed-wing aircraft. After thefixed-wing aircraft contacts the flexible capture member, themulti-copter 10 carries the full weight of both the flexible capturemember and the fixed-wing aircraft. The fixed-wing aircraft must then belowered down toward the ground. If the fixed-wing aircraft contacts theflexible capture member close to the ground, less time will be requiredto lower the aircraft toward the ground than if the fixed-wing aircraftmakes contact higher up toward the multi-copter 10. A low contact pointresults in less time flying the multi-copter 10 at peak load (i.e.,while fully supporting the fixed-wing aircraft), meaning that lessenergy is used.

The drawback to a low contact point, however, is that when thefixed-wing aircraft 20 makes contact low toward the ground it imparts ahigh overturning moment on the structure on the ground (i.e., thestorage assembly 2000 and monopole assembly such as the articulatablemonopole assembly 4000). To reduce the effect of this high overturningmoment, in various embodiments, the monopole assembly such as thearticulatable monopole assembly 4000 of this disclosure is configuredabsorb certain forces such as by articulating when the overturn momentexceeds a threshold. This enables the base structure (i.e., storageassembly 2000) to be less heavy while still providing a sufficientstructure to support the monopole assembly such as the articulatablemonopole assembly 4000 and fixed-wing aircraft 20 after it has beencaptured and lowered.

FIGS. 4A-4H illustrate one example embodiment of the articulatablemonopole assembly 4000 and its components. This illustrated examplearticulatable monopole assembly 4000 includes: (1) an articulating joint4100, and (2) an upstanding pole structure 4200. In this disclosure, theterm “articulatable monopole assembly” may be used to describe variousembodiments of the monopole assembly, including embodiments in which thearticulating joint is articulatable, the upstanding pole structure isarticulatable, or both.

The illustrated example articulating joint 4100 includes: (1) a jointbase 4110, (2) a spring 4140, (3) an upper coupling assembly 4160, and(4) a plurality of ligaments 4190.

The illustrated example joint base 4110 includes a lower joint plate4112 and a plurality of lower ligament connectors 4122.

The illustrated example lower joint plate 4112 includes a substantiallyflat lower surface 4114. The lower surface 4114 faces and is in contactwith the top surface of the lateral monopole support plate 2300. Thelower joint plate 4112 and the lateral monopole support plate 2300 arecoupled together via the plurality of mounting bolts 2310 a-d. The lowerjoint plate 4112 includes an upper surface 4116. The lower joint plate4112 defines a lower spring receiving recess 4118. The lower springreceiving recess 4118 is cylindrical in shape, and is configured toreceive a first end of the spring 4140. The lower joint plate 4112 alsoincludes a cylindrical side surface 4120. The plurality of lowerligament connectors 4122 extend radially from the cylindrical sidesurface 4120 perpendicular to a longitudinal axis of the articulatablemonopole assembly 4000. The plurality of lower ligament connectors 4122are spaced evenly around a circumference of the lower joint plate 4112.As discussed below, respective first ends 4192 of the plurality ofligaments 4190 are configured to be attachable to the plurality of lowerligament connectors 4122. The joint base 4110 defines a central opening(not shown) through which the flexible capture member 5000 extends. Thejoint base is also positioned coaxially with the mounting component 3900of the downhaul winch assembly 3000, and the lateral monopole supportplate 2330 of the monopole mounting assembly 2300. This enables theflexible capture member to extend from the downhaul winch assembly 3000though the joint base 4110 of the articulating joint 4100.

The illustrated example spring 4140 is coupled on a first end to thelower spring receiving recess 4118 of the lower joint plate 4112. Thespring is coupled on a second end to the upper spring receiving recess4166 of the upper joint plate 4162. The spring 4140 includes appropriatecharacteristics (stiffness, spring constant, etc.) such that theupstanding pole structure 4200 of the articulatable monopole assembly4000 remains substantially upright when the fixed-wing aircraft 20 issupported by the upstanding pole structure 4200 via the flexible capturemember 5000 (e.g., FIG. 4A). The spring 4140 also has appropriatecharacteristics such that it supports the upstanding pole structure 4200and the fixed-wing aircraft 20 when it is preloaded or compressed viathe plurality of ligaments 4190. The spring 4140 is positioned coaxiallywith the mounting component 3900 of the downhaul winch assembly 3000,the lateral monopole support plate 2330 of the monopole mountingassembly 2300, and the lower spring receiving recess 4118 of the lowerjoint plate 4112. This enables the flexible capture member 5000 toextend through the spring 4140.

The illustrated example upper coupling assembly 4160 includes an upperjoint plate 4162, a plurality of upper ligament connectors 4182, andside pins 4184.

The illustrated example upper joint plate 4162 includes a lower surface4164. The upper joint plate 4162 defines an upper spring receivingrecess 4166. The upper spring receiving recess 4166 is configured toreceive a second end of the spring 4140. The upper joint plate 4162includes a top surface 4170. The plurality of upper ligament connectors4182 extend from the top surface 4170. The plurality of upper ligamentconnectors 4182 are spaced evenly around the top surface 4170, andextend parallel to the longitudinal axis of the articulatable monopoleassembly 4000. As discussed below, respective second ends 4194 of theplurality of ligaments 4190 are configured to be attachable to theplurality of upper ligament connectors 4182. The upper coupling assembly4160 also includes side pins 4184. The side pins extend perpendicularlyto the longitudinal axis of the articulatable monopole assembly 4000.The side pins couple the upper joint plate 4162 to the upstanding polestructure 4200. The upper joint plate 4162 has a top surface 4176defining an aperture 4178 configured to receive the upstanding polestructure 4200. The upper coupling assembly 4160 defines a channel (notshown), to enable the flexible capture member 5000 to extend through it.

The illustrated example articulating joint 4100 includes a plurality ofligaments 4190. The plurality of ligaments 4190 are fibrous, braided,and are configured to stretch when a force is applied. The plurality ofligaments 4190 include respective first ends 4192 coupled to the lowerligament connectors 4122, and respective second ends 4194 coupled to theupper ligament connectors 4182. The plurality of ligaments 4190 arepositioned evenly around the circumference of the articulating joint4100. The plurality of ligaments are configured to preload the spring4140, such that the spring is partially compressed in a default orinitial stage prior to capture of the fixed-wing aircraft 20.

The amount of force provided by the plurality of ligaments 4190 topreload the spring 4140 is determined based on an amount of supportneeded to counteract the weight of the upstanding pole structure 4200and the dangling fixed-wing aircraft 20 against windage (e.g., FIG. 4A),compared with a force required to allow the upstanding monopolestructure 4200 to bend in response to an impact of the fixed-wingaircraft contacting the flexible capture member 5000. A low amount ofpreloaded force on the spring causes the spring to bend easier inresponse to an impact force from the fixed-wing aircraft contacting theflexible capture member 5000. At the same time, however, the lowpreloaded force can causes the articulatable monopole assembly to bendat rest when the fixed-wing aircraft is being supported by thearticulatable monopole assembly 4000 (e.g., FIG. 4A). On the other hand,a high amount of preloaded force causes the spring 4140 to bend lessreadily, meaning that the articulatable monopole assembly 4000 is morerigid, increasing the likelihood that the articulatable monopoleassembly 4000 and storage assembly 2000 tip over in response to theforce from the fixed-wing aircraft 20 contacting the flexible capturemember 5000. At the same time, however, the high preloaded force enablesthe articulatable monopole assembly 4000 to remain upright when thefixed-wing aircraft is lowered down and supported by the articulatablemonopole assembly in wind, as in FIG. 4A.

The present disclosure contemplates that it may be desirable for anoptimal range of preload force and spring rate to be used, such that therelatively rigid upstanding monopole structure 4200 bends over when thefixed-wing aircraft contacts the flexible capture member 5000, causing asufficient moment to be exerted on the articulatable monopole assembly4000, but is rigid enough to remain upright when the fixed-wing aircraftis lowered to the ground in windy conditions. The articulating joint4100 is configured to absorb a portion of the energy from the contact bystretching the spring 4140 and plurality of ligaments 4190. By absorbingat least a portion of the force from the impact of the fixed-wingaircraft, the articulatable monopole assembly 4000 and storage assembly2000 are less likely to tip over. Further, by absorbing at least some ofthe force, the fixed wing aircraft is able to contact the flexiblecapture member lower to the ground (i.e., closer to the articulatablemonopole assembly 4000) and with greater speed than would otherwise bepossible, without causing the articulatable monopole assembly 4000 andstorage assembly 2000 to tip over.

The illustrated example upstanding pole structure 4200 includes a lowermast segment 4210, a middle mast segment 4220, an upper mast segment4230, and an upper guiding component 4240. These members are illustrateddisassembled in FIG. 2A, and assembled in FIGS. 4A and 4D.

The illustrated example lower mast segment 4210 is coupled at a firstend to the upper joint plate 4162 of the articulating joint 4100, and tothe middle mast segment 4220 at a second end. The lower mast segment4210 is hollow, such that the flexible capture member 5000 can extendthrough the middle of the lower mast segment 4210. The middle mastsegment 4220 is removably attached to the lower mast segment 4210 at afirst end, and removably attached to the upper mast segment 4230 at asecond end. The middle mast segment 4220 includes padding 4222 which isconfigured to protect the upstanding pole structure 4200 and variouscomponents of the fixed-wing aircraft 20 when they make contact as shownin FIG. 4A. The middle mast segment 4220 is also hollow. The upper mastsegment 4230 is removably attached to the middle mast segment 4220 at afirst end, and to the upper guiding component 4240 at a second end. Theupper mast segment 4230 includes padding 4232 which is similar oridentical to the padding 4222. The upper mast segment 4230 is hollow.

The illustrated example upper guiding component 4240 is coupled to theupper mast segment 4230. As best shown in FIGS. 4E, 4F, and 4G, theupper guiding component 4240 includes a tubular body 4242, a tubularmounting element 4244, lower and upper roller bearings 4250 a and 4250b, a retaining element 4252, a needle bearing supporter 4254, andmultiple needle bearings 4260.

The illustrated example body 4242 defines a cylindrical interior surfacethat forms a flexible capture member receiving bore therethrough. Themounting element 4244 surrounds part of the body 4242. The upper rollerbearing 4250 b surrounds part of the body 4244 and is positioned betweenan upper surface (not labeled) of the mounting element 4244 and a lip(not labeled) of the body 4242. The lower roller bearing 4250 asurrounds part of the body 4242 and is positioned between a lowersurface (not labeled) of the mounting element 4244 and the retainingelement 4252, which is disposed within a channel defined around thecircumference of the body 4242. The retaining element 4252 retains thebody 4242, the mounting element 4244, and the roller bearings 4250 a and4250 b in place relative to one another. The needle bearing supporter4254 is attached to the body 4242 via fasteners, and the needle bearings4260 are rotatably attached to the needle bearing supporter 4254 suchthat they can rotate relative to the needle bearing supporter 4254.

The illustrated example mounting element 4244 of the upper guidingcomponent 4240 is fixedly attached to the upper mast segment 4230 of theupstanding pole structure 4200. After attachment, the roller bearings4250 a and 4250 b enable the body 4242 and the attached needle bearingsupporter 4254 and needle bearings 4260 to rotate together about thelongitudinal axis of the body 4242.

5. Flexible Capture Member

The flexible capture member 5000 is used to facilitate retrieval of thefixed-wing aircraft 20 from free, wing-borne flight and to retrieve themulti-copter 10 after fixed-wing aircraft launch and retrieval. Theflexible capture member 5000 may be a rope (such as a Spectra rope) orother similar element. In the embodiment shown in the figures, theflexible capture member 5000 includes a multi-copter connection portion5100 connected to (such as tied to or integrally formed with) afixed-wing aircraft retrieval portion 5200. The multi-copter connectionportion 5200 and/or the fixed-wing aircraft retrieval portion 5200 maybe configured to stretch or lengthen in response to an impact from thefixed-wing aircraft contacting the flexible capture member 5000, asshown in FIG. 5B.

6. Methods of Operation

As described in detail below, the multi-copter 10, the storage assembly2000, the downhaul winch 3000, the articulatable monopole assembly 4000,and the flexible capture member 5000 are usable to retrieve thefixed-wing aircraft 20 from free, wing-borne flight. An examplemulti-copter-assisted fixed-wing aircraft retrieval method is describedbelow as being conducted from the ground. However, it should beappreciated that the present disclosure contemplates that themulti-copter-assisted fixed-wing aircraft retrieval method describedherein may be conducted from any suitable moving or stationary object,including boats, ships, trailers, and more.

FIGS. 5A-5D diagrammatically show retrieval of the fixed-wing aircraft20 from free, wing-borne flight via use of the multi-copter 10, thestorage assembly 2000, the downhaul winch 3000, the articulatablemonopole assembly 4000, and the flexible capture member 5000.

To retrieve the fixed-wing aircraft 20 from free, wing-borne flight, theoperator positions the storage assembly 2000 at a retrieval location,and assembles the articulatable monopole assembly 4000 as shown in FIG.4A. The operator extends the flexible capture member 5000 from thedownhaul winch 3000 through the articulatable monopole assembly 4000,such that the flexible capture member extends out of a top of thearticulatable monopole assembly 4000 through the upper guiding member4240. The operator then removably attaches the flexible capture member5000 to the multi-copter 10. The multi-copter 10 is then flown up intothe air, such that the flexible capture member extends upwardly from thearticulatable monopole assembly 4000, providing a target for thefixed-wing aircraft to hit in order to be captured and retrieved.

The downhaul winch may provide a resistive force to remove the slackfrom the flexible capture member 5000, and to maintain a set tension onthe flexible capture member 5000 prior to, during, and/or after thefixed-wing aircraft makes contact with the flexible capture member 5000.This may be done via a hydraulic system coupled to the downhaul winch3000.

As shown in FIG. 5A, the multi-copter 10 either automatically or viaoperator control executes a station-keeping operation relative to thearticulatable monopole assembly 4000. The fixed-wing aircraft iscontrolled to contact and capture the flexible capture member 5000 whichextends between the articulatable monopole assembly 4000 and themulti-copter 10.

The impact of the fixed-wing aircraft 20 on the flexible capture memberpropagates through the flexible capture member into both themulti-copter 10 and the articulatable monopole assembly 4000. If theforce is great enough (i.e., a large enough moment is exerted on thearticulatable monopole assembly), it causes the articulatable monopoleassembly to bend at the articulating joint 4100, which enables thearticulatable monopole assembly 4000 to absorb the force without tippingthe articulatable monopole assembly 4000 and storage assembly 2000 over.Some of the force is also propagated into the multi-copter, whichabsorbs the force by moving sideways in the direction of the impartedforce. As noted above, the use of the articulating joint 4100 of thearticulatable monopole assembly 4000 enables the fixed-wing aircraft tocontact the flexible capture member at a lower position, closer to thearticulatable monopole assembly 4000 than the multi-copter 10. Thisenables the articulatable monopole assembly 4000 to absorb a much largerforce relative to the multi-copter, such that the multi-copter does notneed to expend as much energy to remain in position above thearticulatable monopole assembly 4000. As such, a less powerfulmulti-copter can be used, and less battery power or fuel is needed.

After capture of the fixed-wing aircraft, the multi-copter operatorcontrols the multi-copter 10 to descend toward the articulatablemonopole assembly 4000. As the multi-copter is lowered, the downhaulwinch 3000 winds the flexible capture member to maintain tension. Thiscontinues until the fixed-wing aircraft 20 has reached the top of thearticulatable monopole assembly, and is at rest (e.g., FIG. 4A). Themulti-copter 10 can be lowered to the ground and the fixed-wing aircraftcan then be removed from the flexible capture member 5000. Afterlanding, the multi-copter operator shuts the multi-copter 10 down,detaches the flexible capture member 5000 from the multi-copter 10, andremoves the multi-copter 10 to a hangar (or other suitable area) fordisassembly and storage.

7. Additional Example Embodiments

FIGS. 6A-6E illustrate a second example embodiment of the aircraftretrieval device, the downhaul winch 13000, the monopole assembly 14000,the flexible capture member 15000, and the outrigger supports 16000A and16000B, as well as an example storage assembly 12000 of the presentdisclosure.

The storage assembly 12000 may be similar or identical to the storageassembly 2000 described above in one or more respects. Storage assembly12000 is configured to store various components of the aircraftretrieval system, including the downhaul winch 13000, parts of themonopole assembly 14000 including the articulating joint 14100 and theupstanding monopole structure 14200, the flexible capture member 15000,and the outrigger supports 16000A and 16000B. Furthermore, the storageassembly 12000 is configured to act as a base to support the aircraftretrieval assembly, and specifically the monopole assembly, duringoperation. As illustrated in FIGS. 6A-6E, the monopole assembly isattached to the storage assembly 12000 at a first end. The outriggers16000A and 16000B are rotated and extended radially outward from themonopole assembly 14000 and storage assembly 12000, such that a tripodof support for the monopole assembly 14000 is formed by the storageassembly 12000, first outrigger support 16000A, and second outriggersupport 16000B.

The downhaul winch 13000 may be similar or identical to the downhaulwinch 3000 described above. For simplicity, the description of thedownhaul winch 13000 will not be repeated in this section.

The example monopole assembly 14000 includes: (1) an articulating joint14100, and (2) an upstanding pole structure 14200.

The illustrated example articulating joint 14100 includes: (1) a jointbase 14110, (2) a spring 14140, (3) an upper coupling assembly 14160,and (4) a plurality of ligaments 14190. The illustrated example jointbase 14110 includes a lower joint plate 14112 and a plurality of lowerligament connectors 14122. Various components or features of theaircraft retrieval device shown in FIGS. 6A-6E are similar or identicalto the components and features described above. For example, the jointbase 14110 may be similar or identical to the joint base 4110, thespring 14140 may be similar or identical to spring 4140, and the uppercoupling assembly 14160 may be similar or identical to the uppercoupling assembly 4160. The components shown in FIGS. 6A-6E may havedifferences as well. For example, the upper ligament connectors 14182shown in FIG. 6C extend radially outward from the upper couplingassembly 14160, while the upper ligament connectors 4182 shown in FIG.4D extend in an upward direction. Various other differences will beapparent from the Figures.

The illustrated example upstanding pole structure 14200 includes a lowermast segment 14210, a middle mast segment 14220 (surrounded at leastpartially by padding 14222), an upper mast segment 14230, and an upperguiding component 14240. Various components of the upstanding monopolestructure 14200 may be similar or identical to the upstanding monopolestructure 4200, and for simplicity are not described again in thissection.

Flexible capture member 15000, shown in FIG. 6A, may be similar oridentical to flexible capture member 5000 described above.

The example embodiment shown in FIG. 6A-6E includes first and secondoutrigger supports 16000A and 16000B, which enable a larger footprintfor the base of the aircraft retrieval system to lower the risk oftipping over during operation. The outrigger supports 16000A and 16000Bare comprised of multiple sections that are attachable together. Incertain example embodiments, such as the example shown in FIG. 6D, thesections of each outrigger support are fully detachable from each other.Alternatively, the multiple sections may be connected in a telescopicmanner, such that a first section slides into and out of a secondsection. The outrigger supports 16000A and 16000B may be rotatablyattached to the storage assembly 12000, as shown in FIGS. 6A, 6B, 6C,and 6E. The outrigger supports 16000A and 16000B may be configured torotate from a storage position shown in FIG. 6E, to an operationalposition shown in FIGS. 6A, 6B, and 6C. Each outrigger support includesa first end rotatably attached to the storage assembly 12000, and assecond end that extends outward from the storage assembly 12000 suchthat a tripod is formed. Each outrigger support 16000A and 16000B alsoincludes a secondary support member 16010A and 16010B that is attachableto the outrigger support at a first end, and to the storage assembly12000 at a second end. This provides additional stability to theoutrigger supports.

FIGS. 7A-7D illustrate additional features of various embodiments of thepresent disclosure. In particular, FIGS. 7A-7D illustrate an examplecastellated masthead 7000 and an example mid-mast pad 8000.

The example castellated masthead 7000 includes a cylindrical base 7100and a plurality of upstanding triangular portions 7200A-C. Thecylindrical base 7100 is suitably attached to the top of the upstandingmonopole structure (e.g., such as monopole structure 4200 or monopolestructure 14200). The flexible capture member is extendible through acenter hole 7010 of the castellated masthead 7000.

The upstanding triangular portions 7200A-C are curved such that togetherthey form a cylindrical upper portion of the castellated masthead 7000,as shown in FIG. 7D. While the castellated masthead 7000 is illustratedhaving three upstanding triangular portions 7200A-C, it should beunderstood that two, four, or some other quantity of upstandingtriangular portions can be used. Further, while the upstandingtriangular portions are illustrated as being triangular in shape, isshould also be understood that other suitable shapes may be used aswell. Each upstanding triangular portion includes a rounded or flattenedapex 7210A-C, and two side edges 7220A-C and 7222A-C. The side edges ofadjacent upstanding triangular portions point or extend toward slots7300A-C.

The portions that define the slots 7300A-C are sized to grip theflexible capture member that extends through the center hole 7010.During the capture process, after the fixed-wing aircraft engages thecapture member, the fixed-wing aircraft is held aloft by, for example, amulti-copter. As the multi-copter lowers the fixed-wing aircraft downtoward the monopole assembly, the flexible capture member is reeled in.At a certain point in this process, the fixed-wing aircraft is lowereddown below the height of the monopole structure, and any furtherlowering of the fixed-wing aircraft would cause the flexible capturemember to pay out from the winch. At this point, the fixed-wing issupported by the monopole structure and flexible capture member. Theflexible capture member connected to the fixed-wing aircraft hangingdown from monopole structure is guided into and caught in one of theslots 7300A-C. Friction between the flexible capture member and portionsthat define the respective slot causes the flexible capture member toremain caught in the slot, and the fixed-wing aircraft is thereaftersupported by the monopole structure without the need for high tension onthe flexible capture member by the winch. This enables the winch to beset at a tension that is less than the weight of the fixed-wingaircraft, and still be able to hold the fixed-wing aircraft off theground when the fixed-wing aircraft is supported by the monopolestructure as shown in FIGS. 7A-C.

FIGS. 7A and 7B illustrate a second embodiment of the paddingsurrounding a portion of the upstanding monopole structure. This paddingis shown as padding 8000 in FIGS. 7A and 7B. Padding 8000 includes aconical upper surface 8100 that enables the fixed wing aircraft to slidedown alongside the upstanding monopole structure, without snagging orgetting caught on the upper surface of the padding 8000. The uppersurface of the padding is conical with a minor diameter 8110 above amajor diameter 8120, wherein the minor diameter 8110 is matched to theouter diameter of the upstanding monopole structure, and wherein themajor diameter 8120 is matched to the outside diameter of the padding8000.

8. Example Variations

The examples disclosed herein are described using a multi-copter tocarry one end of the flexible capture member to a predetermined height,such that the fixed-wing aircraft can make contact with the flexiblecapture member below the height of the multi-copter. However, it shouldbe appreciated that a different system, vehicle, or other device may beused to hold the first end of the flexible capture member aloft. Forexample, embodiments of the present disclosure may instead use a crane,boom, aircraft (either fixed-wing or not), parachute, balloon, or otherelement to provide a high point for the flexible capture member.

Various changes and modifications to the presently preferred embodimentsdescribed herein will be apparent to those skilled in the art. Forexample, in certain scenarios, it may be beneficial to route theflexible capture member along the outside of the monopole, like afishing rod, rather than concentrically within the diameter of themonopole.

Further, the downhaul winch may be replaced by an alternative tensioningdevice, such as a bungee, piston, or falling weight.

These changes and modifications can be made without departing from thespirit and scope of the present subject matter and without diminishingits intended advantages. It is intended that such changes andmodifications be covered by the appended claims.

1. An aircraft retrieval device comprising: a flexible capture membercouplable to a lifting device on a first end, the lifting deviceconfigured to raise the first end of the flexible capture member to apredetermined height; a tensioning device, couplable to a second end ofthe flexible capture member; a monopole assembly; and an upper guidingcomponent configured to guide the flexible capture member with respectto the monopole assembly.
 2. The aircraft retrieval device of claim 1,wherein the monopole assembly is an articulatable monopole assembly. 3.The aircraft retrieval device of claim 1, wherein the monopole assemblyincludes an articulating joint and an upstanding monopole structure. 4.The aircraft retrieval device of claim 3, wherein the articulating jointis preloaded to a predetermined value based on a weight of (i) amonopole base structure and footprint, (ii) windage, and (iii) anaircraft to be supported by the monopole structure.
 5. The aircraftretrieval device of claim 4, wherein the articulating joint is preloadedto the predetermined value based on an impact force expected from anaircraft impacting the flexible capture member.
 6. The aircraftretrieval device of claim 3, wherein the articulating joint includes asteel coil spring.
 7. The aircraft retrieval device of claim 6, whereinthe articulating joint includes a plurality of fibrous rope ligamentsconfigured to preload the spring to a predetermined value.
 8. Theaircraft retrieval device of claim 1, further including a storageassembly including a monopole mounting assembly configured to supportthe monopole assembly.
 9. The aircraft retrieval device of claim 8,wherein the monopole mounting assembly is configured to fit in thestorage assembly.
 10. The aircraft retrieval device of claim 1, whereinthe monopole assembly includes an upstanding monopole structure thatincludes a plurality of removably attached mast segments.
 11. Theaircraft retrieval device of claim 10, wherein the plurality ofremovably attached mast segments are configured to fit in a storageassembly.
 12. The aircraft retrieval device of claim 1, wherein themonopole assembly includes an upstanding monopole structure thatincludes padding configured to protect the upstanding monopole structureand a captured aircraft supported by the monopole assembly.
 13. Theaircraft retrieval device of claim 12, wherein an upper surface of thepadding is conical, with a minor diameter above a major diameter, andwherein the minor diameter is matched to an outer diameter of theupstanding monopole structure, and wherein the major diameter is matchedto an outside diameter of the padding.
 14. The aircraft retrieval deviceof claim 1, wherein the base of the monopole assembly is supportable bya combination of a storage assembly base and outrigger supports.
 15. Theaircraft retrieval device of claim 14, wherein the monopole assembly issupported by outrigger supports including telescopic tubes that extendradially outward from the monopole assembly.
 16. The aircraft retrievaldevice of claim 1, wherein the tensioning device is a downhaul winch.17. The aircraft retrieval device of claim 1, wherein the tensioningdevice is regulated to payout when tension exceeds a predetermined upperlimit, wherein the predetermined upper limit is based on a risk ofcapsize.
 18. The aircraft retrieval device of claim 1, wherein thetensioning device is regulated such that a static weight of the capturedfixed-wing aircraft is held against gravity when the fixed-wing aircraftis supported by the monopole assembly.
 19. The aircraft retrieval deviceof claim 1, including a castellated masthead configured with portionsthat define slots sized to receive the flexible capture member as aweight of the fixed-wing aircraft transfers to the monopole structure,such that one or more of the portions can grip the flexible capturemember.
 20. The aircraft retrieval device of claim 1, wherein themonopole structure is composed of a lightweight material includingfiber-reinforced plastic, aluminum or titanium.
 21. The aircraftretrieval device of claim 1, wherein the monopole structure is composedof a non-conductive material including fiberglass reinforced plastic.22. An aircraft retrieval device comprising: a flexible capture membercouplable to a lifting device on a first end of the flexible capturemember; a tensioning device couplable to a second end of the flexiblecapture member; a monopole assembly; and a support structure comprising:first and second outrigger supports, and a storage assembly, wherein thefirst and second outrigger supports and the storage assembly form atripod to support the monopole assembly.
 23. The aircraft retrievaldevice of claim 22, wherein the monopole assembly is supportable by thestorage assembly, and wherein the first and second outrigger supportsare configured to attach to the storage assembly and extend radiallyoutward from the monopole assembly.
 24. The aircraft retrieval device ofclaim 22, wherein each of the first and second outrigger supportsincludes multiple sections removably attached together to form theoutrigger support.